A Walking Pattern Generator around Singularity

Abstract

Humans utilize the extended-knee configuration to achieve efficient walk. A humanoid robot, however, cannot do so, since this posture is a singular one, and hence, an extremely large joint velocity would be generated, provided a conventional control method is used. Some other methods exist, though, that are able to handle motion control at such postures. One example is the Singularity Consistent (SC) Approach, which we used in a previous work to generate a static walk for a humanoid robot. In this paper, we propose a new method to generate a dynamic walking pattern through the singularity neighborhood, by using proper ankle control and pattern generation based on a spherical inverted pendulum model. Experimental results show the effectiveness of this approach.

Walking control based on the SIPUP model

“…In our previous work, we found that the approach direction to the singularity is important when the leg moves around the singularity neighborhood [7]. Fig.…”

“…The joint angles can be calculated using the conventional inverse Jacobian around the singularity without extremely large joint velocities, if the velocity component in the radial direction is kept sufficiently small. In order to achieve such a trajectory, we have proposed a walking pattern generator based on the spherical inverted pendulum model [7]. As a result, motion within the singularity neighborhood without excessive joint angular velocity can be achieved in the middle of the sup- (point B).…”

Walking pattern generation involving 3D waist motion for a biped humanoid robot

“…Kurazume et al proposed a straight legged walking pattern by controlling the height of the CoG trajectory according to the state of the ZMP (Zero-Moment Point [11]) controller [12]. Sekiguchi et al proposed a walking pattern generation method through the neighborhood of the singularity by using ankle control based on the spherical inverted pendulum model [13]. Kim et al considered the knee joint fully stretched while designing the hip trajectory in the sagittal plane [14].…”

Walking gait generation using linear inverted pendulum model for biped robot with heterogeneous legs

“…The common methods belonging to model analysis include, inverse pendulum model, passive model and mass-spring model, etc. Withine theme, linear inverted pendulum model are widely studied and used successfuly in many biped robot system [5][6] [7]. Figure 1 shows the prototype of the test-bed in heterogeneous configuration.…”